A silicon semiconductor is a material that has been conventionally investigated for materials for thin-film transistors (TFT) and solar cells.
In formation of a pattern of a silicon thin film used for integrated circuits and thin-film transistors, a silicon film is generally formed through a vacuum process such as a CVD process. In a method for this formation, the vacuum process is used. Therefore, a large-scale device is required. Further, there are problems in which handling is difficult since a gas is used as a raw material.
In order to solve the problems, there is a procedure in which a silane polymer is dissolved in an organic solvent, applied to a substrate, baked, and dehydrogenated to form a silicon film.
For example, a method in which a solution composition containing cyclopentasilane is prepared, applied to a substrate, and then irradiated with an ultraviolet light, and the obtained coating film is heated to form a silicon film is disclosed (see Patent Document 1).
A method for producing a silane polymer including irradiating a photopolymerizable silane compound with a light having a wavelength of 405 nm to produce a silane polymer having a weight average molecular weight that is measured by gel permeation chromatography in terms of polystyrene of 800 to 5,000 is described (see Patent Document 2).
A semiconductor thin film-forming silane composition containing (A) a solid polysilane compound synthesized by irradiating cyclopentasilane with a light having a wavelength of 170 to 600 nm, (B) cyclopentasilane, and (C) at least one compound selected from a boron compound, an arsenic compound, a phosphorus compound, and an antimony compound, characterized in that the solid polysilane compound (A) is dissolved, and the ratio of the polysilane compound (A) to the cyclopentasilane (B) is 0.1 to 100% by weight is disclosed (see Patent Document 3).
Silylcyclopentasilane used as a radical initiator for ring-opening polymerization of cyclopentasilane is disclosed (see Patent Document 4).
A composition containing an oligosilane or polysilane consisting of hydrogen and silicon and/or germanium and having a molecular weight of 450 to 2,300, which, after coating a substrate with the composition and/or printing the composition to form an oligo- or polysilane film, and then curing, forms an amorphous, hydrogenated semiconductor film having a carbon content of 0.1% by atom or less is disclosed (Patent Document 5). This document describes that oligosilane or polysilane is synthesized using a heterogeneous catalyst consisting of a transition metal element of Group 7 to 12 or a substrate-anchored derivative thereof.